Double acting, reciprocating hot gas, external combustion cylinder-piston engine

ABSTRACT

To provide a compact engine construction in which the operating piston-cylinder units and the associated regenerator, condenser and re-heater units are located closely adjacent, with gas connections of minimum length, the cylinder units are combined into one aligned row forming the longitudinal axis of the engine. The regenerator and condenser units for each of the cylinders are placed in common housings, preferably also of cylindrical shape and size similar to and not less than that of the cylinders such that the central axis of the cylinders and the central axis of the common housings paired therewith are placed in planes perpendicular to the longitudinal axis of the machine. The hot gas connection means are all placed in planes which are perpendicular to the machine axis and the cold gas connection means are inclined at an angle to the plane perpendicular to the machine axis. The re-heaters are preferably formed as a wall of tubes extending in a plane parallel to the longitudinal axis of the machine, the cylinders, as well as the cylindrical housings for the regenerator and condensers being formed with similar manifolds connecting to the re-heater tube wall.

Tusche DOUBLE ACTING, RECIPROCATING HOT GAS, EXTERNAL COMBUSTIONCYLINDER-PISTON ENGINE Inventor: Eckhard Tusche, Augsburg,

Germany M.A.N. Maschinenfabrik Augsburg-Numberg Aktiengesellschaft,Augsburg, Germany [73] Assignee:

Filed: Mar. 29, 1973 Appl. No.: 346,107

Foreign Application Priority Data Apr. 8, 1972 Germany 2217078 US. Cl.60/24 Int. Cl. F03g 7/06, F25b 9/00 Field of Search 60/24 8/1949 VanWeenan 60/24 11/1952 Van Weenan 60/24 9/1970 Bush 60/24 PrimaryExaminer-Edgar W. Geog hegan Assistant Examiner-H. Burks, Sr. Attorney,Agent, 0r Firm-Flynn & Frishauf [57] ABSTRACT To provide a compactengine construction in which the operating piston-cylinder units and theassociated regenerator, condenser and re-heater units are locatedclosely adjacent, with gas connections of minimum length, the cylinderunits are combined into one aligned row forming the longitudinal axis ofthe engine. The regenerator and condenser units for each of thecylinders are placed in common housings, preferably also of cylindricalshape and size similar to and not less than that of the cylinders suchthat the central axis of the cylinders and the central axis of thecommon housings paired therewith are placed in planes perpendicular tothe longitudinal axis of the machine. The hot gas connection means areall placed in planes which are perpendicular to the machine axis and thecold gas connection means are inclined at an angle to the planeperpendicular to the machine axis. The reheaters are preferably formedas a wall of tubes extending in a plane parallel to the longitudinalaxis of the machine, the cylinders, as well as the cylindrical housingsfor the regenerator and condensers being formed with similar manifoldsconnecting to the reheater tube wall.

14 Claims, 6 Drawing Figures PATENTEUHAR 5 \974 SNEH 1 Bf 2 Fig.1

DOUBLE ACTING, RECIPROCATING HOT GAS, EXTERNAL COMBUSTIONCYLINDER-PISTON ENGINE CROSS REFERENCE TO RELATED APPLICATIONS U.S. Ser.No. 317,778, filed: Dec. 22, 1972; US. Ser. No. 315,930, filed: Dec. 18,1972 US. Ser. No. 352,711 filed Apr. 19, 1973.

The present invention relates to a double acting piston-cylinder engineof the external combustion, hot gas type and more particularly to suchan engine which has a plurality of cylinders located in a row, thecylinders forming the longitudinal axis of the engine.

In engines of this type, the hot space, and the cold space of thecylinder are sub-divided by the working piston. The working piston isconnected to a piston rod and the piston rod, in turn, to the usualcrankshaft forming the rotary or mechanical output of the engine. Thehot space of any one cylinder is connected to the cold space of anothercylinder, with interposition of a heater unit, a regenerator, and acooling unit or condenser. The cooling unit is connected to a line orconnection duct which terminates in the cold space of any cylinder otherthan the hot space of the cylinder which is connected to the re-heaterunit.

Hot gas piston-cylinder engines of this type have previously beendescribed. The construction and arrangement of the cylinders,re-heaters, cooler and other components require, usually, comparativelylong flow paths for the gases. The comparatively long flow paths leadingfrom one cylinder to another cylinder, between which further cylindersmay be disposed, result in a gas volume within the line which may belarge with respect to the maximum displacement volume of the workingspaces and the cylinders themselves. As a result, high line losses willresult, which in turn results in low efficiency of the overall engineconstruction. A compara tively high volume of working fluid is requiredin order to fill such an engine. The working fluid may be a gas such ashelium and the smaller the overall volume of the engine can be held,with respect to working volume of the pistons, the more efficient willbe the use of the gas which is employed in the engine.

It is an object of the present invention to provide a double actingcylinder-piston hot gas multiple cylinder engine in which the componentsof the engine are so arranged that losses due to long interconnectionlines are held to a minimum and which results in improved overall engineoperating efficiency.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, the double actingcylinder-piston units are located all along a line row to form thelongitudinal axis of the machine. Any one cylinder is paired with aregenerator and cooler, which are located in a common housing. Thelongitudinal axes of any one cylinder and of a regenerator and housingpaired therewith are located in planes perpendicular to the longitudinalaxis of the machine. The flow paths forming the hot lines are arrangedparallel to a plane perpendicular to the longitudinal axis of themachine. The flow paths forming the cold ducts are located at an angleinclined to a plane perpendicular to the longitudinal machine axis.

The specific arrangement of the operating cylinderpiston units and the,preferably cylindrical, common housings of the regenerator-cooler unitspermits construction of an in-line motor with any desired number ofcylinders in modular form. Various cylinder-type piston units and commonhousings for the regenerators and coolers, all similar, can be locatednext to each other, and assembled together as desired, resulting in anarrow and short overall engine construction. The hot lines areextremely short, since each cylinder has the associatedregenerator-condenser placed immediately adjacent thereto, so thatexpansion of materials, resulting from heating of the construction, willbe held to a minimum. Placing the hot lines in a plane perpendicular tothe longitudinal axis of the machine also permits easy accessibility tothe cylinder-regenerator units facilitating gas-tight connection,initial assembly, and subsequent maintenance.

The invention will be described by way of example with reference to theaccompanying drawings, wherein:

FIG. 1 is a highly schematic, perspective illustration of an in-linefour-cylinder engine in which the regenerator housings are located atopposite sides of the cylinders, in sections;

FIG. 2 is a schematic top view, illustrating the flow paths of theengine of FIG. 1;

FIG. 3 is a schematic top view, illustrating flow paths, of an in-linesix-cylinder motor in which the regenerator-cooler units are placed atopposite sides of the row of cylinders, in sections;

FIG. 4 is a schematic top view of an in-line sixcylinder engine in whichthe regenerator-cooler units are paired, and sectionally located atopposite sides of the cylinder row;

FIG. 5 is a schematic top view illustrating flow paths of afour-cylinder engine in which the regeneratorcooler housings are locatedon one side of the cylinder row; and

FIG. 6 is a schematic top view illustrating flow paths ofa six-cylindermotor in which the regenerator-cooler housings are located at one sideof a cylinder row.

The engine of FIG. 1 has four cylinders l, 2, 3, 4. Each cylinder has apiston 5 therein which sub-divides the cylinder into an upper, or hotworking space 6 and a lower or cold working space 7. Each piston 5 isconnected to a piston rod 8, schematically shown, which in turn isconnected to a crankshaft 9, also shown only schematically. Cylindersl-4 are each connected to a regenerator and a cooler, located in acommon housing 10, 11, 12, 13, respectively. Housings 10 and 11,associated with cylinders 1 and 2 are located, as seen in FIG. 1, behindthe rear row of cylinders. Housings 12 and 13 associated with cylinders3 and 41 are located at the opposite side of the cylinders 3 and 1.Behind housings 10 and 11 and behind housings 12, 13, respectively, afree space will be available in which a burner unit, such as a burner 20(only one being shown, and this burner being shown schematically) can belocated. This arrangement results in a very compact engine in whichspace is highly efficiently utilized. Cylinders l-4 have longitudinalaxes AA. The common housings 10-13 also are cylindrical and havelongitudinal central axes B-B. The cylinder axes AA of all the cylindersare located in a plane, perpendicular to the longitudinal axis of themachine. The longitudinal axis of the machine lies in a plane commonwith the main bearings of crankshaft 9. The arrangement in which'thelongitudinal axes AA of the cylinders 1-4 and BB of the common housings-13 are in parallel planes, perpendicular to the machines longitudinalaxis results in shortest connecting paths between cylinders 1-4 and theassociated housings containing a regenerator and a cooler. Cylinders1-4, as well as housings 10-13 have, located at their top side, at equalheight, manifolds 14, 15, respectively. These manifolds are joinedtogether. The manifolds 14 associated with cylinders 1-4 are connectedto the manifolds associated with housings 10-13 are an array ofre-heater tubes 16. The tubes 16, each, are bent in U-shaped form toform a tube wall, in which the gaseous medium for operation of theengine is heated. These tubes thus are the heat exchanger between burnerand the heating medium. The tube walls are schematically shown at 17,18. The housings 10-13 for the regenerator-cooler assembly arecylindrical, and have preferably the same diameter, and the samediameter as cylinders 1-4. Shaping cylinders 1-4 and housings 10-13 tobe similar permits construction of the manifolds 14, 15 to be identical,which substantially reduces costs in manufacture, stocking of repair andreplacement parts and assembly costs. The manifolds 14, 15 need not beidentical, however, and need not be joined intermediate their combinedlengths. They could also be joined at different locations, for exampleabove the common housings 10-13. Such an arrangementdecreases the volumeof the manifolds 15, thus decreasing the dead overall volume of thehousings 10-13 and the associated manifold. Decreasing this dead volumeimproves the efficiency of the engine. Additionally, space is obtainedabove the cylinders 1-4 to permit better placement of the burner 20. Theregenerator-cooler housings 10-13 may have a diameter which is largerthan that of cylinders 1-4, resulting in a particularly short andslightly wider, but highly compact overall construction of the engine.The flow paths are extremely short, thus further improving theefficiency of the engine as a whole.

Ducts 19 are connected to the cold space 7 of the cylinders 1-4, each.The ducts cut the axes defined by the planes A-A and BB, that is, arelocated at an angle with respect to planes perpendicular to thelongitudinal axis of the engine and, each, extend to one of the housings10-13 respectively. Ducts 19 are so placed that, at the most, one of theplanes defined by the axes A-A and BB is intersected, resulting in shortducts. Ducts 19 connect the cold space 7 of a first cylinder with thehousing containing a regenerator and a cooler, and then with theassociated manifold. Connected to the manifold is a wall of tubes, whichconnects to the manifold of the hot space 6 of another cylinder, forexample the manifold of the hot space of the adjacent second cylinder.Thus, for example, hot space 6 of cylinder 1 is connected to the coldspace 7 of the cylinder 2. The region of the flow path from theregenerator to the hot space 6 forms the hot portion of the path; theregion from the cold space 7 to the cooler forms the cold portion of theflow path.

The working fluid, for example helium, has heat applied thereto as itflows through the heater tubes 16. Burner 20 conducts hot gases to theheater tubes 16, located in the walls 17, 18. Burner 20 is placedadjacent the wall of tubes 18 and located next to the row of cylindersplaced oppositely housings 12 and 13. Burner 20 may, however, be placeddifferently, for example above cylinders 3, 4. The flow path of thecombustion gases from burner 20 is indicated by the heavy arrow 21. Theburner providing heat to wall 17 has been omitted from the drawings forclarity, the direction of flow of combustion gases being indicated byarrow 22. The heater tubes 16 of at least two adjacently placedcylinders form one complete connected tube wall, extending parallel tothe longitudinal axis of the machine. This location of the cylinders,and the location of the tube walls faciliates heat transfer from theburner to the Working medium and thus improves the efficiency of themachine as a whole. The several heater tubes 16, preferably, are all ofthe same length and shape, so that the flow paths of the heated and hotgaseous medium are all of the same length. This results in uniform heattransfer. The heater tubes 16 are thermally highly loaded. Uniform heattransfer from the burner 20 to the working fluid is efficient, andavoids thermal overload of any one of the components in the system.

The flow paths between cylinders 1-4 and the regenerator-cooler housingsare schematically illustrated in FIG. 2, which also is used as anindication of the schematic representation of flow path in thesubsequent FIGS. 3-6, so that the construction of the engines of FIGS.3-6 will be clear by analogy of the constructional details shown in FIG.1 with the schematic representation shown in FIG. 2. In the schematicrepresentation, the hot lines are shown as double lines 23, and the coldlines as chain-dotted lines 24. The hot space 6 of cylinder 1 isconnected to the cold space 7 of cylinder 2. Hot space 6 of cylinder 2is connected to the cold space 7 of cylinder 4. Hot space 6 of cylinder4 is connected with the cold space 7 of cylinder 3. Hot space 6 ofcylinder 3 is connected back to the cold space 7 of cylinder 1. Each ofthe connections includes a common housing of a regenerator-cooler unit.

The cylinders 1 and 4 and housings 10 and 13 associated therewith areconnected by short lines, bridging the space between a pair ofcylinders. These lines, of course, are the cold lines. An arrangementcan also be constructed in which two long lines connect to the housings10 and 13, bridging two cylinder distances, the short lines thenconnecting the remaining housings 11, 12. The hot lines 23, as can beseen from FIG. 2, are very short and of equal length. This arrangementis provided by placement of the cylinders 1-4 in a plane perpendicularto the longitudinal axis of the machine and likewise placing housings10-13 in planes perpendicular to the longitudinal axis of the machine.The cold lines 24 are not of equal length. The arrangement is so taken,however, that at most one cylinder is between a pair of connectedcylinders, so that the differences in length between the cold connectingline are held to a minimum. The connection of the cylinders also permitsroughly parallel placement of all cold lines, without cross-overs, sothat they can be assembled and connected easily.

FIG. 3 illustrates a six-cylinder engine. Six cylinders 25 are locatedin a row. Each cylinder 25 has a common housing 26 associated therewith,each housing 26 including a regenerator and a cooler. The housings 26are grouped in sections, located at opposite sides of the cylinder row,each section comprising three housings 26. Hot lines 27 again have theminimal length, connecting transversely to the longitudinal axis of themachine. Cold lines 28 are so placed, in accordance with the presentinvention, that at the most, the distance of two cylinders have to bebridged. The length ofthe cold lines is so distributed, similar to theconstruction of FIG. 2, that the two outer housings have short coldlines applied thereto, and the inner housings have longer cold linesconnected. An alternate construction can also be used, in which the twoouter housings have the longer cold lines applied, and the innerhousings the short ones.

FIG. 4 illustrates a group of cylinders 29, arranged in a row, in whichthe housings 31 are placed in sections, each one comprising two suchhousings, the sections alternating at both sides of the rows ofcylinders. Cold lines 32, as discussed in connection with FIG. 3, are soplaced that only short cold lines are connected to the two outerhousings.

The example of FIG. 4 illustrates a four-cylinder engine in whichcylinders 33 are connected by hot lines 34 with respective housings 35,each one containing a regenerator and a cooler. In contrast to FIG. 2,however, the housings 35 are all located on one side of the row of thecylinders 34. The cold lines 36 are distributed as discussed inconnection with FIG. 2. FIG. 6 illustrates an in-line six-cylinderengine in which the cylinders 37 are connected over hot lines 38 withhousings 39, which are all located on one side of the cylinder row. Coldlines 40, as referred to in connection with the discussion of FIG. 3,are connected such that the cold space of the first and last cylinder ofa row is connected to the hot space of an adjacent cylinder. Thearrangement can be altered, however, as shown in FIG. 3, in which thecold lines 36 connect the hot space of the first and last cylinder,respectively, with the cold space of an adjacent cylinder.

Various changes and modifications may be made within the inventiveconcept.

I claim: 1. Double acting reciprocating hot gas external combustionpiston-cylinder engine comprising a group of adjacently placed cylinders(1, 2, 3, 4, 25,

29, 33, 37) which are located in an aligned row defining thelongitindual axis of the engine, the cylinders being subdivided by thepistons into a hot cylinder space (6) and a cold cylinder space (7); aregenerator and cooler for each of the cylinders and a re-heater (16);

cold gas connection means (24, 28, 32, 36, 40) connecting the coldcylinder space (7) of any one cylinder with the respective cooler,regenerator and re-heater;

hot gas connecting means (23, 27, 30, 34, 38), connecting theregenerator to the hot space of another cylinder and including saidre-heater;

a common housing (10, 11, 12, 13; 26, 31, 35, 39)

for the regenerator and cooler;

wherein the common housing (-13; 26, 31, 35, 39)

of a regenerator and cooler is paired with a respective cylinder, andthe central axis of any cylinder, and the central axis of any commonhousing paired with a cylinder are located in planes perpendicular tothe longitudinal axis of the machine;

the hot gas connection means (23, 27, 31), 34, 38) are parallel to aplane perpendicular to the longitudinal axis of the machine;

and the cold gas means (24, 28, 32, 36, 40) are inclined at an angle tothe plane perpendicular to the longitudinal axis of the machine.

2. Machine according to claim 1, wherein the common housings aresub-divided into sections, one section of the common housings beinglocated at one side of the row of cylinders, with respect to thelongitudinal axis of the machine, and another section of the commonhousings being located at the other side of the row of cylinders. (FIGS.1,2,3,4).

3. Machine according to claim 2, wherein the two sections are of equallength.

4. Machine according to claim 2 (FIG. 4), wherein the groups of thecommon housings are alternately arranged at opposite sides of the row ofcylinders.

5. Machine according to claim 1 (FIGS. 5, 6), wherein all the commonhousings (35, 39) are, located in a row at the same side of thecylinders.

6. Machine according to claim 1, wherein the connection means to thecylinder spaces form flow paths and wherein the flow path of gas betweentwo cylinders (14, 25, 29, 33, 37) comprises not more than oneadditional intervening cylinder.

7. Machine according to claim 1, wherein the hot space (6) of the firstcylinder (1) in a row and the hot space of the last cylinder (4) in therow are connected with the cold space (7) of the respective adjacentlylocated cylinder (2, 3). (FIGS. 2, 3, 4, 5).

8. Machine according to claim 1, wherein the cold space of the first andlast cylinder in a row communicates with the hot space of the respectiveadjacently located cylinder (FIG. 6).

9. Machine according to claim 1, wherein the common housings arecylindrical.

10. Machine according to claim 9, wherein the diameter of the commonhousings are at least as great as that of the cylinders.

11. Machine according to claim 9, including manifolds (14, 15) securedto the cylinders and the common housings to conduct gases to and fromthe re-heaters wherein the manifolds applied to the cylinders and thecommon housings are similar.

12. Machine according to claim 1, wherein the hot gas connection meansare dimensioned to provide flow paths of approximately equal lengths.

13. Machine according to claim 1, wherein the reheater means (16) of atleast two adjacently located cylinders (1, 2; 3, 4) form an essentiallycontinuous wall of tubes extending in planes (17, 18) parallel to thelongitudinal axis of the machine.

14. Machine according to claim 13, further comprising burner means (20)located at one side of the wall of tubes (17, 18) opposite to that atwhich the common housings (10-13) are located, the burner meansgenerating heat to heat the tubes of the wall of tubes and hence the gasoperating medium for the engine within the heater tubes.

1. Double acting reciprocating hot gas external combustionpiston-cylinder engine comprising a group of adjacently placed cylinders(1, 2, 3, 4, 25, 29, 33, 37) which are located in an aligned rowdefining the longitindual axis of the engine, the cylinders beingsubdivided by the pistons into a hot cylinder space (6) and a coldcylinder space (7); a regenerator and cooler for each of the cylindersand a reheater (16); cold gas connection means (24, 28, 32, 36, 40)connecting the cold cylinder space (7) of any one cylinder with therespective cooler, regenerator and re-heater; hot gas connecting means(23, 27, 30, 34, 38), connecting the regenerator to the hot space ofanother cylinder and including said re-heater; a common housing (10, 11,12, 13; 26, 31, 35, 39) for the regenerator and cooler; wherein thecommon housing (10-13; 26, 31, 35, 39) of a regenerator and cooler ispaired with a respective cylinder, and the central axis of any cylinder,and the central axis of any common housing paired with a cylinder arelocated in planes perpendicular to the longitudinal axis of the machine;the hot gas connection means (23, 27, 30, 34, 38) are parallel to aplane perpendicular to the longitudinal axis of the machine; and thecold gas means (24, 28, 32, 36, 40) are inclined at an angle to theplane perpendicular to the longitudinal axis of the machine.
 2. Machineaccording to claim 1, wherein the common housings are sub-divided intosections, one section of the common housings being located at one sideof the row of cylinders, with respect to the longitudinal axis of themachine, and another section of the common housings being located at theother side of the row of cylinders. (FIGS. 1,2,3,4).
 3. Machineaccording to claim 2, wherein the two sections are of equal length. 4.Machine according to claim 2 (FIG. 4), wherein the groups of the commonhousings are alternately arranged at opposite sides of the row ofcylinders.
 5. Machine according to claim 1 (FIGS. 5, 6), wherein all thecommon housings (35, 39) are located in a row at the same side of thecylinders.
 6. Machine according to claim 1, wherein the connection meansto the cylinder spaces form flow paths and wherein the flow path of gasbetween two cylinders (1-4, 25, 29, 33, 37) comprises not more than oneadditional intervening cylinder.
 7. Machine according to claim 1,wherein the hot space (6) of the first cylinder (1) in a row and the hotspace of the last cylinder (4) in the row are connected with the coldspace (7) of the respective adjacently locatEd cylinder (2, 3). (FIGS.2, 3, 4, 5).
 8. Machine according to claim 1, wherein the cold space ofthe first and last cylinder in a row communicates with the hot space ofthe respective adjacently located cylinder (FIG. 6).
 9. Machineaccording to claim 1, wherein the common housings are cylindrical. 10.Machine according to claim 9, wherein the diameter of the commonhousings are at least as great as that of the cylinders.
 11. Machineaccording to claim 9, including manifolds (14, 15) secured to thecylinders and the common housings to conduct gases to and from there-heaters (16); wherein the manifolds applied to the cylinders and thecommon housings are similar.
 12. Machine according to claim 1, whereinthe hot gas connection means are dimensioned to provide flow paths ofapproximately equal lengths.
 13. Machine according to claim 1, whereinthe reheater means (16) of at least two adjacently located cylinders (1,2; 3, 4) form an essentially continuous wall of tubes extending inplanes (17, 18) parallel to the longitudinal axis of the machine. 14.Machine according to claim 13, further comprising burner means (20)located at one side of the wall of tubes (17, 18) opposite to that atwhich the common housings (10-13) are located, the burner meansgenerating heat to heat the tubes of the wall of tubes and hence the gasoperating medium for the engine within the heater tubes.